will headers from a 351M fit either of the other 351's? why not if not please I checked summit and it doesnt say it wont but it doesnt say it will either it only says for 77 1/2 and up maybe because that when they started the 351M? heres what I have found at summit http://www.summitracing.com/parts/hed-89210/overview/
No..... The 351m and 400m are based on the 351c but are a tall deck block, They use the Cleveland head not a Windsor.....
Also the bolt patterns are different, Clevelands are diagonal and Windsors are horizontal. There are some aftermarket 289/302/351 Windsor heads that have dual bolt patterns to use the Cleveland headers to take advantage of their larger exhaust ports. The old AR-1/Ford Motorsport J302 aluminum heads had these dual bolt patterns, I have these on my Mexican 302 build.....
Cleveland exhaust ports are also at a steep angle low to the head where the Windsor is a more of a straight shot out of the head, right at the towers - that is why a 351C is actually less trrouble to instal than a 351W
To answer your question - YES! The 351M/400 style headers will fit a 351C 2bbl head. As the others said, will not fit a 351W and they will also not fit a 351C with 4bbl heads. SPark
